Stockholders' Equity and Stock Based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee awards		$ 0	$ 124,259	$ 43,280
Capitalized stock-based compensation	$ 458	0	458	0
Total stock-based compensation expense	124,717	0	124,717	43,280
Employee awards:
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee awards	124,259	0	124,259	44
Secondary transaction
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee awards	0	0	0	43,236
Cost of revenue | Employee awards:
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee awards	3,983	0	3,983	0
Research and development | Employee awards:
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee awards	36,823	0	36,823	8
Sales and marketing | Employee awards:
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee awards	40,465	0	40,465	7
General and administrative | Employee awards:
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total employee awards	$ 42,988	$ 0	$ 42,988	$ 29